low tech testing of home-made insulation?

[mintcake]

Hi,
Does anyone have any ideas about a low-tech,  home-build method of testing the insulating power of home made heat-riser stuff? (e.g. perlite/clay mixes?)

I'd like the tests to be done "at-heat" rather than based on a steam jacket or something, but I'm struggling to come up with anything that would work.

I've tried making a tunnel of 1cm x 1cm x 4cm test samples on a bit of scrap ytong, with a blow-torch flame down the middle. I put little cups of aluminium foil on the samples and a couple of drips of water in each cup, hoping to time how long the water would last, or how many drips would evaporate in a minute.

Net result was that I couldn't see the water well enough to time anything, and at about 1 drip a minute I struggled to maintain a constant heat.

Other than putting some dye in the water, which I've just thought of, does anyone have any better ideas?

I have a thermocouple for my multimeter somewhere, but it's been missing for a few months. I also have a couple of temperature-voltage converter chips which will die at about 110C.

[photoman290]

you could try making a drip feed oil heater based on the spike design. that will get hot enough to turn ss flexy flue liner bright red. my IR thermometer only goes up to 500C but i can get my little burner a lot hotter than that. all you need is a cast iron pot and some 5 inch flue pipe. i use a drip feed as the heater is my main source of heat. but for testing risers all you need to do is pour around 1 inch of diesel or heating oil in the pot light it and put a flue on it. my flue is around 6 feet. that will get you up to around 600C i would think maybe higher. of course do it somewhere where you wont have people complaining as the flame will be about 10 foot long. there are a few designs on youtube most are really danerous, bnuit for a good simple calibrated heat source they should work a treat.

[Deleted]

Without a thermometer your fingertips are the best sensors available.
If you can touch a surface only for a very hort time it will have about 60°C.
With thick callus it could be a bit more
Make some not to thick discs and stop the time it takes until you cannot longer touch it,
if the other side it heated with a with a blow-torch.

[mintcake]

Hi, and thanks for the ideas.
With a longer, wider, thinner sample and a better water trough, I've now got some data - see my local clay/perlite/charcoal thread if you're curious.
5 drips of water and a 7mm thick sample give a boil-away time of about a minute and a half.